Good question on the window while using the ring switcher. I have the same problem and do not see an obvious answer to it either.

As far as the wall plugin it is not in an official release yet, but is in head for svn. Depending on your distro there may be someone building packages based on the nightly builds but I would use that with caution.

Note: I think, though I am not positive, that the Wall plugin is distinct from the plane plugin. The plane plugin was removed from core because it was rarely used if I recall correctly. The wall plugin uses the same plane concept but is distinct.

Under the Appearance tab when in the "Application Window Switcher" page in the beryl-settings-manager, down the bottom there is an expandable set of options called "Rotating List". Once expanded, check the box labelled "Fade windows out when using ring switcher".